Discharge grille and an air curtain device

ABSTRACT

The invention relates to a blow-out grid, the peripheral form and dimensions of which correspond to an elongate form of a blow-out opening of an air curtain device. This blow-out grid comprises slats which extend in use longitudinally and transversely relative to the lengthwise direction of the blow-out grid and which guide in a desired uniform direction respective transversely and longitudinally diverging components of an airflow passing therethrough. The invention further relates to an air curtain device, comprising: a housing; means generating an airflow in the housing; an elongate blow-out opening with an inner peripheral form; a channel between the means generating an airflow and the blow-out opening; and a blow-out grid arranged in the blow-out opening and having a peripheral form and dimensions corresponding to the elongate form of the blow-out opening, and wherein the blow-out grid is one from the group comprising blow-out grids.

The present invention relates to a blow-out grid and an air curtain device.

In the art of blow-out grids and air curtain devices it is generally known that use can be made of a blow-out grid in a blow-out opening of the air curtain device for the purpose of correctly guiding and orienting an airflow blown out using the air curtain device. Use is generally made, as desired, of a blow-out grid with longitudinal slats or of a blow-out grid with transverse slats, depending on the consideration as to the direction in which some degree of divergence is still allowed. The choice for a specific type of blow-out grid with longitudinal slats or with transverse slats is of course also related to the choice of a specific type of motor or fan serving as the means for generating an airflow in the air curtain device.

The use in air curtain devices of radial fans with blades curved to the rear has for instance greatly increased in recent times. The reason for this is that such radial fans with blades curved to the rear have favourable properties, particularly compared to other types of fan. This particularly relates to favourable ratios between airflow capacities, pressure build-up, cost, weight, sound and the possibilities of carrying out maintenance. The present invention is of course not limited hereto however.

Such and other known fans, which find wide use in air curtain devices at the present time, do not have only favourable properties. Such fans thus generate airflows with various directional components therein. Such directional components can be disadvantageous in respect of the final orientation of the air curtain to be generated with the air curtain devices. Determined parts of a passage or opening to be covered with the air curtain can for instance remain uncovered by the air curtain, which thus reduces the effectiveness of the air curtain device.

The present invention has for its object to obviate, or at least alleviate, the above stated and other drawbacks and imperfections of the prior art, for which purpose a blow-out grid is provided as is defined in the appended independent claim number 1. The use of such a blow-out grid in an air curtain device is further defined in independent claim number 13.

With a blow-out grid according to the present invention in an air curtain device according to the present invention the orientation of an airflow generated by a fan in the air curtain device can be improved in efficient manner. By guiding all these components in the right direction an air curtain can be generated with the desired properties and coverage, irrespective of the properties of the fan used in the air curtain device.

Preferred embodiments of a blow-out grid according to the present invention are defined in the dependent claims 2-12. Claim 2 for instance relates to the property that the longitudinal and the transverse slats form sets positioned one above the other. These slats can have a mutual connection per individual set, or the longitudinal and the transverse slats can be mutually connected in the sets so as to provide a unified whole. The turbulence which would result from the longitudinal and the transverse slats all being combined in a single height or layer, and thus having a form defining a square in top view, can herein be avoided by providing the longitudinal and the transverse slats in sets above each other.

Providing a set with the transverse slats has a favourable effect on the reduction of turbulence, particularly in the longitudinal direction. The intermediate distance between the longitudinal slats can thus be made greater or the height of the longitudinal slats can be made smaller. Both measures can however be implemented, and it is in any event the case that use of material can be minimized. The costs can hereby also be kept as low as possible.

In a further preferred embodiment the blow-out grid according to the invention can have the feature that at least some of the longitudinal and the transverse slats are connected to each other in order to form a unified whole. By connecting the longitudinal and transverse slats to each other at selected positions an at least one connecting bar or rod through the slats can be omitted, which results in a material-saving and therefore also in a saving in the production costs of manufacturing the blow-out grid.

In yet another preferred embodiment the blow-out grid according to the present invention has the feature that the transverse slats have a design associated with the longitudinal divergence of the airflow other than the design of the longitudinal slats associated with the transverse divergence. The longitudinal slats can thus be designed to guide the airflow coming from the fans in the air curtain devices (vertically) downward in parallel manner. In the case of some fans however, the airflow generated thereby has a subordinate, less strong divergence in the longitudinal direction of the blow-out grid and, in order to nevertheless guide this subordinate, less strong component in the same direction as the main flow using the longitudinal slats, the transverse slats can also have a different design because they are intended for the purpose of guiding another part of the airflow.

In the case of the radial fans with blades curved to the rear the longitudinal component is usually considerably weaker than the transverse component. It is thus possible to suffice with fewer transverse slats in order to nevertheless guide these longitudinal components of the airflows generated with the fans in the desired direction.

In a further preferred embodiment a blow-out grid according to the present invention can have the features that the distance between the transverse slats is greater than between the longitudinal slats. This can be related to the “different” design of the transverse slats relative to the design of the longitudinal slats. It is further possible that only two transverse slats are applied, on which, or preferably under which, the longitudinal slats are then arranged or fixed. The transverse slats can thus serve as suspension and as mutual connection for the longitudinal slats. The function can then be fulfilled of the usual connecting bars or rods, which can per se cause an annoying turbulence, this being avoided by using the transverse slats. The transverse slats can then also serve as suspension.

It is further possible for an embodiment of a blow-out grid according to the present invention to have the feature that at least one of the transverse and the longitudinal slats have in cross-section a form adapted to the relevant component of the airflow passing therethrough during use. Such a form can be a curvature or an oblique position relative to a vertical, whereby the direction of origin of an airflow for guiding is related to the exit direction of this airflow from the blow-out grid.

In a further preferred embodiment the edges of the slats oriented in the blow-out direction are given a straight form, i.e. transversely of the blow-out direction, against vortex shedding and against noise nuisance. Straight can be understood to mean that the slats can be trimmed or cut off and thus have an angular form, from which the airflow separates quickly. A less favourable effect is obtained when said edges of the slats are rounded, as can result from an extrusion process.

In a further preferred embodiment a blow-out grid according to the present invention can have the feature that at least one of the longitudinal and the transverse slats are mutually engaging in order to provide a connection therebetween. This can also be a particular feature of the manner of mutually connecting the transverse and the longitudinal slats, to the extent the engagement also provides a coupling or fixing. A saving of space can hereby also be made in the height, and therefore of the space required for the blow-out grid.

A further preferred embodiment of a blow-out grid according to the invention can have the feature that at least some of the longitudinal and the transverse slats are disposed at a distance from each other. This is a particularly favourable embodiment where the available overall height for the blow-out grid is a less critical consideration and wherein very favourable effects are obtained in respect of the alignment or the guiding of the various components in the different directions of the airflow generated with a fan. In such an embodiment said distance is preferably substantially smaller than the width or height of the wider or higher of the longitudinal and transverse slats. It has been found and/or is anticipated that the desired effects can hereby still be obtained of guiding in the desired direction all the components of the airflow running in different directions.

As noted above, the present invention also relates to an air curtain device. This device then comprises a housing and airflow-generating means in the housing. A blow-out opening is further provided with an inner peripheral form, and a channel runs from the airflow-generating means to the blow-out opening. Then further arranged in the blow-out opening is a blow-out grid with a peripheral form and dimensions corresponding to the elongate form of this blow-out opening. The blow-out grid is then a grid according to the present invention and the air curtain device as a whole is thereby also an embodiment of this invention.

In a preferred embodiment of an air curtain device according to the present invention the airflow-generating means are of a type which generates, at least at the position of the blow-out grid, an airflow further also having a longitudinal component as well as a transverse component. A possible embodiment hereof can be formed by the per se known radial fans with blades curved to the rear. The use hereof has diverse advantages, as already stated above. An extremely good and effectively aligned air curtain can be generated by the combination of such radial fans with blades curved to the rear and a blow-out grid according to the present invention. At least two radial fans with blades curved to the rear are preferably disposed in the housing of the air curtain device in an orientation parallel to the blow-out opening and to the blow-out grid therein. For the purpose of an effective use of space, the channel can herein have a curvature of about 90°, whereby the need to align the airflows generated by such fans is clearly apparent.

A number of embodiments of the present invention will be described hereinbelow in more detail with reference to the annexed drawings, in which similar or the same components, elements and parts are designated with the same reference numerals and in which:

FIG. 1 shows a partly cut-away perspective view of an air curtain device with a blow-out grid therein, both according to the present invention;

FIG. 2 shows a perspective view of a part of a blow-out grid according to the present invention;

FIG. 3 shows a perspective view of another embodiment of a part of a blow-out grid according to the present invention; and

FIG. 4 shows yet another embodiment of a part of a blow-out grid according to the present invention;

FIG. 5 shows another embodiment of a part of a blow-out grid according to the present invention; and

FIG. 6 show an alternative embodiment of a part of a blow-out grid according to the present invention.

FIG. 1 shows an air curtain device (1) in an embodiment according to the present invention. This device comprises a housing (2) in which fans (3) are disposed. Fans (3) are disposed in an array parallel to a blow-out opening (4). A blow-out grid (5) is arranged in blow-out opening (4).

A channel (6) extends between the fans (3), which are in particular fans of the type “radial fan with blades curved to the rear”, toward the blow-out opening (4).

An airflow generated with fans (3) in the direction of arrow A has directional components upon arrival at blow-out opening (4) and blow-out grid (5). The main flow is designated by arrow A. It will be apparent from FIG. 1 that the main flow, designated by arrow A, of the airflow generated with fans (3) has a deviation relative to the vertical direction desirable for blowing out. This is for instance the case when the air curtain device is disposed at a doorway or similar passage. In order to guide the main flow corresponding with arrow A vertically, longitudinal slats (7) are arranged in blow-out grid (5). These slats are disposed vertically, and the dimensions and intermediate distances between the longitudinal slats (7) cause the main flow corresponding with arrow A to be guided downward after passing through the curve in channel 6.

The airflow coming from the fans further also comprises a longitudinal component which is designated by arrow B and arrow C. Depending on the properties of the fans used, substantially one of the two indicated longitudinal components of arrow B and arrow C will occur, although the occurrence of both longitudinal components of arrow B and arrow C is not precluded.

In order to also guide the longitudinal components corresponding with arrow B and arrow C in vertically downward direction, blow-out grid (5) also comprises transverse slats (8). Since the longitudinal components along arrow B and arrow C in an airflow generated with fans (3) will normally be weaker than the main flow which is indicated by arrow A and which is substantially defined by the selection of determined fans and the form of channel 6—in particular the curvature therein—and the enclosure in the housing, the intermediate distance between transverse slats (8) can be selected to be considerably greater than the intermediate distance between longitudinal slats (7).

Precisely in the case where fans (3) are chosen from the type of a radial fan with blades curved to the rear, and such fans (3) are all disposed in the same orientation, one of the transverse components indicated by arrow B and arrow C will again be even stronger than the other transverse component. In such a situation it can be favourable to adjust the orientation or design of transverse slats (8) hereto. This can be achieved in a design shown by way of example in FIG. 2, FIG. 3 or FIG. 4.

FIG. 2 shows a part of a blow-out grid, the longitudinal slats (7) of which are substantially the same as the longitudinal slats (7) in blow-out grid (5) in FIG. 1. Transverse slats (8) are however disposed at an angle to the vertical. In this embodiment transverse slats (8) are therefore oriented in relation to the origin of the longitudinal component of the airflow designated by arrow B or arrow C in FIG. 1.

FIG. 3 shows a similar situation, but transverse slats (8) here not only have an oblique position relative to the vertical but also a curvature which is again intended to intercept as much as possible of the longitudinal components in an airflow and guide them downward in vertical direction. Conversely, FIG. 4 shows another embodiment wherein the transverse slats have a substantially vertical orientation and are simultaneously curved or have a curved surface, once again for the purpose of maximum interception and guiding of a transverse component of an airflow generated with fans, depending on the origin of this airflow with such longitudinal components therein.

The present invention is thus described in considerable detail. Diverse additional and alternative embodiments will occur to the skilled person, which alternative and additional embodiments must be deemed as designs within the scope of the present invention, as that scope is defined in the appended claims. It is for instance possible that longitudinal slats (7) and transverse slats (8) can be connected to each other or fixed to each other in various ways. It is for instance possible here to dispense with mutual connections between the longitudinal slats, as are for instance formed in conventional blow-out grids by means of connecting bars or rods. This function can be fulfilled by transverse slats (8). Such mounting tubes or bars can however also occur in embodiments of the present invention. The transverse slats form a set, and the same applies for the longitudinal slats. The set with transverse slats (8) can also have many designs other than slats extending only in transverse direction and substantially upright as shown in the figures and described above. It is equally possible for use to be made here of honeycomb structures, designs defining squares and so on.

There are various embodiments, dimensions and dimensioning presently provided by the inventors of the present invention. It is for instance assumed that the height, or at least the effective height, of the transverse slats must be approximately as great or greater than the intermediate distance therebetween, thereby avoiding oblique blow-out. The height of the longitudinal slats can for instance amount to 50 mm, while the intermediate distance between the longitudinal slats can amount to 20 mm. In a possible non-limitative preferred embodiment the height of the transverse slats can herein amount to 45 millimetres, with an intermediate distance between the transverse slats of about 50 mm, starting from the embodiment shown in FIG. 1.

It is also possible to choose a smaller height of the transverse slats, for instance 25 mm, in order to prevent oblique blow-out. Transverse slats are then however required for the purpose of downward vertical orientation of the longitudinal component of the airflow generated by the fans.

In a possible preferred embodiment it can be the case that the ratio (height transverse slats+height longitudinal slats)/minus (distance between transverse slats, distance between longitudinal slats) should be at least 5. Any other value at which the intended effects occur can however also result in an embodiment according to the present invention. The grid part or set with the transverse slats also has another favourable effect.

Providing a set with the transverse slats has a favourable effect on the reduction of turbulence, particularly in the longitudinal direction. The intermediate distance between the longitudinal slats can thus be made greater, or the height of the longitudinal slats can be made smaller. It is however possible to implement both measures, and it is in any event the case here that use of material can be minimized. The costs can hereby also be kept as low as possible.

In an embodiment with a distance between the longitudinal and the transverse slats it is provided for that the distance may not be greater than the greatest height, at least the greatest effective height, of the longitudinal slats and the transverse slats. This is to prevent a decrease in effectiveness.

In an alternative preferred embodiment according to the invention the upper set of slats 10 is formed by a number of straight slats (FIG. 5). The lower set of slats 12 is then provided at an angle per slat so as to thereby guide the airflow more toward the centre. In an alternative preferred embodiment the slats of lower set 14 are formed from curved slats (FIG. 6) in order to guide the airflow with reduced resistance. The airflow is also guided in vertical direction by the curvature, thereby reducing possible horizontal components. If desired, it is possible to provide the lower slats with larger dimensions, particularly in the flow direction, in order to thereby improve guiding even further. The dimension of the overall length of the guiding of the airflow in vertical direction herein preferably amounts to at least five times the dimension of a (possibly partly virtual) channel formed by the combination of slat sets. The dimension in the direction of the airflow, in the shown embodiment the vertical direction, can however amount to a multiple of said factor.

It is thus the case that after examination of the foregoing many alternative and additional embodiments can occur to the skilled person which all lie within the scope of the invention defined in the appended claims, unless there is a departure therein from the actual definitions or the spirit of the invention. 

1. Blow-out grid, the peripheral form and dimensions of which correspond to an elongate form of a blow-out opening of an air curtain device, which blow-out grid comprises slats which extend in use longitudinally and transversely relative to the lengthwise direction of the blow-out grid and which guide in a desired uniform direction respective transversely and longitudinally diverging components of an airflow passing therethrough.
 2. Blow-out grid as claimed in claim 1, wherein the longitudinal and the transverse slats form sets positioned one above the other.
 3. Blow-out grid as claimed in claim 1, wherein at least some of the longitudinal and the transverse slats are connected to each other in order to form a unified whole.
 4. Blow-out grid as claimed in claim 1, wherein the transverse slats have a design associated with the longitudinal divergence of the airflow other than the design of the longitudinal slats associated with the transverse divergence of the airflow.
 5. Blow-out grid as claimed in claim 1, wherein the distance between the transverse slats is greater than the distance between the longitudinal slats.
 6. Blow-out grid as claimed in claim 1, wherein at least one of the transverse and the longitudinal slats have in cross-section a form adapted to the relevant component of the airflow passing therethrough during use.
 7. Blow-out grid as claimed in claim 6, wherein during use the slats are disposed at an angle to the vertical.
 8. Blow-out grid as claimed in claim 6, wherein at least during use the slats comprise a curvature.
 9. Blow-out grid as claimed in claim 1, wherein the edges of the slats oriented in a blow-out direction are given a straight form transversely of the blow-out direction, against vortex shedding and against noise nuisance.
 10. Blow-out grid as claimed in claim 1, wherein at least some of the longitudinal and the transverse slats are mutually engaging in order to provide a connection therebetween.
 11. Blow-out grid as claimed in claim 1, wherein at least some of the longitudinal and the transverse slats are disposed at a distance from each other.
 12. Blow-out grid as claimed in claim 11, wherein the distance is substantially smaller than the width or height of the wider or higher of the longitudinal and the transverse slats.
 13. Blow-out grid as claimed claim 1, wherein at least one of the longitudinal or transverse slats has a form and/or orientation varying from perpendicular to the exit direction of the airflow out of the blow-out grid.
 14. Air curtain device, comprising: a housing; means generating an airflow in the housing; an elongate blow-out opening with an inner peripheral form; a channel between the means generating an airflow and the blow-out opening; and a blow-out grid arranged in the blow-out opening and having a peripheral form and dimensions corresponding to the elongate form of the blow-out opening, and wherein the blow-out grid is one from the group comprising blow-out grids as claimed in claim
 1. 15. Air curtain device as claimed in claim 14, wherein the means generating an airflow are of a type which generates at least at the position of the blow-out grid an airflow having a longitudinal component as well as a transverse component.
 16. Air curtain device as claimed in claim 14, wherein the means generating an airflow are of the type known as a radial fan with blades curved to the rear, which by definition generates at least at the position of the blow-out grid the airflow also comprising a longitudinal component as well as a transverse component.
 17. Air curtain device as claimed in claim 16, wherein at least two radial fans with blades curved to the rear are disposed in an orientation parallel to the blow-out opening and to the blow-out grid therein. 